If you're doing the usual pump-and-hold routine, do the right rear first, then left rear, then right front, then left front. Ignore the bleeders on the master cylinder - they serve no useful purpose. If it's a new (dry) master cylinder, bench-bleed it first to get trapped air out of the bore.

when i put on an original booster and master, i first bench bleed the master and then after installation, i blend the bleeders at the wheels and to my surprise it was perfect the first time. i did nothing with the metering block or proportioning valve.

The only time you need to depress the plunger on the back side of the round metering/hold-off valve is if you use a pressure bleeder that generates less than 30-40 psi; that valve opens as soon as it sees about 40 psi, and the pump-and-hold routine does that easily.

Are you pressure bleeding or doing it the old fashioned way. Once when doing old fashoned it took an eternity to get the rears to bleed but it did bleed. Had no options at the time. Did you get the rod length on this system staightened out? Proper free play? Piston in master must return to center to work correctly.

assuming you have addressed the previous issues that sauron327 mentioned:starting at the master cylinder crack the fittings one at a time to check to see where you are getting fluid. retighten before moving to the next one. i would suspect a blockage, maybe in the rubber line that is between the body and rear axle. (i found a blockage in the steel line on the left side of my axle in my '67.) personnally, i use a vaccuum bleeder like the "Mighty-Vac". sears sells one that looks like it was made by the same vender that makes the Mighty-Vac.

Thank you everyone for your helpIt took about 20 minutes per each back cylinder to bleed-but there done.

they work great!

If it really took that long to get fluid to the rears, I'd suspect a partial blockage in the rear flex hose; how old is the hose? (it's dated) When flex hoses age, they deteriorate and swell up/delaminate on the inside (not visible from the outside), forming a restriction to normal fluid flow, and worse, they become a check valve that prevents fluid flow back toward the master cylinder when you take your foot off the brake - that can cause the rear brakes to drag, frying the linings.